The present invention relates to a system for monitoring the water consumption and energy use of water consuming devices and monitoring the energy use of water operated heating and cooling devices in multi-unit building complexes where the individual units are supplied water from a common source and more particularly to a system which will calculate the water consumption and water related energy use of the individual units so that water, sewer and energy costs can be fairly apportioned to the units to encourage conservation. The invention also relates to monitoring unusual water usage to detect leaks and open valves.